<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link href="https://cdn.bootcdn.net/ajax/libs/minireset.css/0.0.2/minireset.min.css" rel="stylesheet" />
  </head>
  <body>
    <style>
      :root {
        font-size: calc(100vw / 375);
      }

      body {
        display: flex;
      }
      div {
        font-size: 15rem;
      }
      div:nth-of-type(1) {
        width: 175rem;
        height: 200px;
        background-color: blueviolet;
        margin-right: 25rem;
      }
      div:nth-of-type(2) {
        width: 175rem;
        height: 200px;
        background-color: red;
      }
    </style>
    <div>1</div>
    <div>2</div>
  </body>
</html>
